Golf club shaft

ABSTRACT

An improved method for preparing a golf club shaft out of a shaft rod is disclosed. This method utilizes a marking directly provided on the shaft rod. The marking may be scale, wording or marks. The marking provides cutting information to be adequately utilized by workers in cutting operations. The marking additionally provides property information of the shaft or a golf club incorporating the shaft.

[0001] This application claims priority from Japanese Patent ApplicationNo. 2000-240832 filed Aug. 9, 2000 entitled “Golf Club Shaft.”

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to a golf club shaft.More particularly, the present invention relates to a method forpreparing a golf club shaft out of a shaft rod utilizing a marking ormarkings provided on the shaft rod, which provide processing informationas well as property information.

[0004] 2. Related Art

[0005] As is generally known and typically shown in FIG. 5, aconventional golf club 100 is typically comprised of an elongated shaft10, a club head 40 integrally having a hosel 60, a socket member 50 anda grip member 70. The hosel 60 receives a tip end portion of the shaft10 and integrally secures the club head 40 thereto with an adhesive.

[0006] The length of the tip end portion of the shaft 10 to be insertedinto the hosel 60 is typically predetermined according to desiredproperties for the shaft 10.

[0007] The socket member 50 is securely mounted on a preset portion ofthe shaft 10 and functions to control the length of insertion of theshaft tip portion into the hosel 60. Typically, such control isimportant to effectively retain the adhesion between the tip portion andthe hosel 60.

[0008] The socket member 50 additionally functions to partially absorbphysical energy or shock that a basal portion of the head 40 or thehosel portion accidentally receives in use and will protect the golfclub 100 from damages such as breaking or cracking in the vicinity ofthe socket member 50.

[0009] Conventional and typical processes to integrate the club head 40onto the club shaft 10 are briefly described hereunder.

[0010] According to designed properties of a shaft 10 such as itsoverall length, weight, diameter, flex, elasticity and stiffness, anoptimum shaft rod is selected.

[0011] The shaft rod is cut at a first distance from its tip and/or at asecond distance from its butt to provide a club shaft 10 having adesigned length for the designed properties of the shaft 10.

[0012] Typically, there is provided a degree of clearance between thesurface of the portion of the shaft 10 inserted in the hosel 60 and theinner surface of the hosel 60 so as to facilitate easy insertion andprovide secure adhesion therebetween with an adhesive. Such clearancemay be provided by grinding or abrading the surfaces of the insertedportion of the shaft 10 and the hosel 60 with appropriate grinding orabrading means.

[0013] Before the insertion, both surfaces are typically washed andthoroughly cleaned. After the insertion, the inserted portion of theshaft 10 is securely integrated with the hosel 60 with a powerful glueor adhesive. A grip member 70 is mounted on a grip portion of the shaft10 and secured thereon to provide a grip of a golf club 100.

[0014] With a conventional method of producing golf clubs, it is notreadily known to workers where exactly to cut shaft rods for particularproperties thereof as there are provided no cutting indications orinformation on conventional shaft rods. Conventionally, workers manuallyprovide cutting markings on shaft rods one by one before individualcutting and then cut the shaft rods at those cutting markings, which islaborious and time consuming.

[0015] With conventional golf clubs, it is not readily known, either,where shaft rods have been cut after tip portions of the shafts havebeen inserted into club heads 40 or grip members are mounted on theshafts. Golfers may wish to know exact properties of their golf clubsthat are subject to the cutting processes.

SUMMARY OF THE INVENTION

[0016] Accordingly, it is an object of the present invention to providea shaft rod with cutting information that facilitates precise andefficient cutting of the shaft rod.

[0017] It is another object of the present invention to provide a golfclub with adequate information about the properties of the golf clubthat have been provided after shaft rod cutting.

[0018] According to the present invention, cutting information isprovided directly on a shaft rod. The cutting information may be amarking provided in a tip portion and/or butt portion of the shaft rod.Such information is provided by letters, marks or colors. Other types ofindications or a blend of a variety of indications may be utilized aswell.

[0019] The shaft rod having such information or a marking is typicallycut according to separately provided cutting instructions that instructworkers where on the marking to cut the shaft rod.

[0020] A golf club comprising or incorporating a shaft prepared or cutin accordance with the present invention provides properties such asflex, torque, stiffness, weight, etc. to the golf club practicallyexactly as desired or designed. Information about the length of theshaft in the golf club may additionally be provided.

[0021] It is therefore possible to provide golf clubs made to orderaccording to individual tastes of golfers who may be extra particularabout individual properties of their golf clubs.

[0022] Such markings provide information where the shaft rod has beencut even after a club head and a grip member have been mounted on theshaft and no traces of cut sections are in view. Golfers looking for agolf club with particular properties can easily find one that exactlysatisfies their desires.

[0023] Such markings can also provide information about the limitationto the distance that can be cut off from a shaft rod. A tip portion of ashaft rod is provided uniformly without tapering. Therefore, if a shaftrod is cut at an excessively long distance from its tip, the shaft isvery likely tapered there. A tapered portion would not be safely securedin a hosel. Such excessive cutting would invite deterioration to theperformance of golf clubs as well.

[0024] A butt end portion of a shaft rod should not be freely cut off,either. Excessive cutting-off might lead to accidental breaking of theadhesion between a grip portion of the shaft and a grip member, forthere would be created excessive gap between the grip portion and thegrip member since the grip portion there would be “too” thin for the“typically mass-produced” grip member.

[0025] As such markings may automatically be provided at the time ofmanufacturing shaft rods, no extra manual marking work is required,greatly saving on labor and processing time.

[0026] It is an additional object of the present invention to provide amethod for preparing a club shaft out of a shaft rod by cutting off anend portion or portions of the shaft rod so as to provide desiredproperties of the shaft or a golf club comprising the shaft.

[0027] It is yet another object of the present invention to provide amethod for readily and efficiently cutting off an end portion orportions of a shaft rod so as to provide designed properties to a shaftprepared out of the shaft rod.

[0028] Other objects of the present invention will be readily understoodby ones skilled in the relevant art by reading the descriptions thatfollow together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1(a) schematically shows a shaft rod to be cut according tothe present invention;

[0030]FIG. 1(b) schematically shows a tip end portion of a shaft rodhaving cutting information thereon according to an embodiment of thepresent invention;

[0031]FIG. 1(c) schematically shows a butt end portion of a shaft rodhaving cutting information thereon according to an embodiment of thepresent invention;

[0032]FIG. 1(d) schematically shows a butt end portion of a shaft rodhaving cutting information thereon according to another embodiment ofthe present invention;

[0033]FIG. 2 schematically shows a club head into which a tip portion ofa shaft having cutting information thereon is inserted according to anembodiment of the present invention;

[0034]FIG. 3 schematically shows a club head into which a tip portion ofa shaft having cutting information is inserted after a larger cut-off;

[0035]FIG. 4 schematically shows a club head into which a tip portion ofa shaft having cutting information is inserted after a largest cut-off;

[0036]FIG. 5 schematically shows a typical golf club;

[0037]FIG. 6(a) is a table of instructions forming part of the presentinvention in an embodiment, according to which workers are instructedwhere to cut shaft rods and golfers can know properties of golf clubs;and

[0038]FIG. 6(b) is another table of instructions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0039] In FIG. 1(a) is shown a shaft rod to be a shaft 1 after goingthrough a cutting step. It is noted that in exceptional cases, it ispossible for a shaft rod to be a shaft 1 without going through anycutting steps. An encircled tip end portion 2 provided in the vicinityof the tip of the shaft 1 or rod is to be inserted into a hosel of ahead. An encircled butt end portion 3 provided in the vicinity of thebutt of the shaft 1 or rod is to provide a grip of a golf club.

[0040] In FIG. 1(b) is shown an enlarged tip end portion 2 on whichcutting information or a marking M in a form of scale S is providedaccording to an embodiment of the present invention. The scale S in thisembodiment is divided or calibrated at 5 mm intervals. Such scale S maybe divided at other intervals such as 10 mm intervals, or 1-13 mmintervals.

[0041] In an alternative embodiment, the scale S is divided at ½ inchintervals. In yet another alternative embodiment, the scale S is dividedat ¼ intervals. The scale S may be provided in other inch units as well.

[0042] In FIG. 1(c) is shown an enlarged butt end portion 3 on whichcutting information or a marking M in a form of scale S is providedaccording to an embodiment of the present invention. The scale S in thisembodiment is divided at 5 mm intervals. Such scale S may be divided atother intervals such as 10 mm intervals, or 1-13 mm intervals.

[0043] In an alternative embodiment, the scale S is provided in inchwith ½ inch intervals. In yet another alternative embodiment, the scaleS is divided at ¼ intervals. Such scale S may be provided in other inchunits as well.

[0044] In FIG. 1(d) is shown an enlarged butt end portion 3 on whichcutting information or a marking M in a form of scale S is providedaccording to an embodiment of the present invention. The scale S in thisembodiment is calibrated at 5 mm intervals. Such scale S may becalibrated at other intervals such as 10 mm intervals, or 1-13 mmintervals.

[0045] The scale S of this embodiment is further provided with numbersindicating distances in millimeter from the butt of the rod in order tofacilitate efficient cutting operation and provide golfers with easilynoticeable information where cutting has been done. The numbers may bereplaced by other letter or mark indications.

[0046] In an alternative embodiment, the scale S is divided at ½ inchintervals. In yet another alternative embodiment, the scale S is dividedat ¼ inch intervals. The scale S may be provided in other inch units aswell.

[0047] The markings of the present invention may be provided on golfclubs such that the markings are not viewed by players who areaddressing a ball using the golf clubs.

[0048] Workers are provided with cutting instructions including tablessuch as shown in FIG. 6(a) or FIG. 6(b) as an example. The cuttinginstructions provide lengths to be cut off from tip ends or butt ends ofshaft rods, or both. The predetermined lengths or distances from theends of shaft rods can be readily and precisely located on the scales S.Workers simply cut the shaft rods according to the instructions.

[0049] Golfers may be provided with information including tables such asshown in FIG. 6(a) or FIG. 6(b) as an example, and can be provided withparticular properties of individual golf clubs from the markings M.

[0050] In FIG. 2 is shown an embodiment of utilization of the presentinvention, where a head 4 having a hosel 6 is mounted securely on a tipend portion of a shaft 1, and a socket member 5 having a height about 10mm is also mounted securely on the shaft 1, the lower face of the socketmember 5 contacting the upper end face of the head 4.

[0051] The tip end portion is provided with a marking M comprising scaleS according to the present invention. The original marking M is 80 mmlong in this embodiment, which may be indicated on the shaft or taughtotherwise. Other original lengths can equally be utilized.

[0052] The scale S in this embodiment is calibrated at 5 mm intervals,of which 10 mm intervals are indicated with longer lines. A measuredlength has been cut off from a tip end portion of the shaft rod inaccordance with cutting instructions.

[0053] In this embodiment, about 30 mm from the tip of the shaft 1 isinserted in the hosel 6 and about 10 mm is covered with the socketmember 5. The shaft portion inserted in the hosel 6 is integrallyadhered with an adhesive to the inner surface of the hosel 6. The socketmember 5 is secured somehow to the shaft portion covered with the socketmember 5.

[0054] In one embodiment, a socket member 5 is heated to expand, and isplaced on an appropriate location of a shaft 1. As the socket member 5is cooled, the socket member 5 is squeezed on the shaft 1 and getstightened on the shaft 1. The tightened socket member 5 controls thedepth of insertion of the shaft tip portion into a hosel 6. In anotherembodiment, a socket member 5 is adhered to the shaft 1 with anadhesive.

[0055] The exposed portion of the scale 5, in this example 40 mm,indicates or teaches viewers the length of the cut-off portion (0 mm inthis embodiment) and provides other information in relation to the cut.An example of properties of a golf club shaft in relation to the lengthsof cut-off portions is provided in the table of FIG. 6(a), which is tobe described in detail later.

[0056] In an alternative embodiment, a zone beyond a “safe” distancefrom the tip or butt of a shaft rod or a “dangerous” zone is indicatedon the marking M in warning color such as red. Other colors may equallybe utilized.

[0057] In FIG. 3 is shown another embodiment of the present invention.In this embodiment, a longer distance (20 mm) has been cut off from thetip of a shaft rod, providing slightly different properties from theforegoing embodiment.

[0058] In FIG. 4 is shown still another embodiment of the presentinvention. In this embodiment, a maximum length (40 mm) for thisparticular embodiment has been cut off from the shaft rod, providingstill different properties.

[0059] As used here, there is a maximum length to be safely cut off froma tip end portion or a butt end portion a shaft rod. Such maximumlengths will differ case by case depending upon physical properties ofshaft rods.

[0060] There is provided a table in FIG. 6(a). This table providesproperties of a shaft, “flex”, “torque”, “club length” and “diameter” inrelation to the lengths of cutoff (0-50 mm). The diameter at the butt ofthis particular shaft rod is 15.60 mm. The letter “5” stands for “stiff”and the letter “X” stands for “extra stiff.” The larger the numberaffixed to the letter “5” or “X”, the higher the stiffness within the“5” level or “X” level. The club length is provided in inch as it iscustomary to use inches for golf clubs. The torque is provided in“°/ft·lb” as it is customary to use this unit.

[0061] The “diameter (shaft tip)” in the table is the diameter asmeasured at the shaft portion which is to contact the upper end of thesocket member 5 after a cut-off. With the shaft rod of this embodiment,the shaft rod portion up to 80 mm from the tip end of the shaft rod isprovided in an identical diameter all through. Past the 80 mm portion,the shaft rod gradually becomes thicker.

[0062] The table shows that the diameter of the shaft measured at thesocket member contacting portion is equal in diameter at 8.65 mm up to40 mm of the “cut length” as the first 40 mm tip end portion of theshaft rod is to be inserted into the hosel 60 of the head 4 and thesocket member 5. The hosel 60 is about 30 mm deep and the socket member5 is about 10 mm tall in this embodiment. This shaft starts changing itsthickness at a distance around 50 mm from the tip end.

[0063] If an excessive length is cut off beyond the 40 mm mark, thehosel 60 is to receive a tapered portion, at least partially, which willnot provide a very secure integration between the hosel 60 and the shaftportion.

[0064]FIG. 6(b) provides another table. In this table all lengths areprovided in inch, and the diameter at the butt of this particular shaftrod is 0.614 inch.

[0065] Golfers who are particular about “flex” and/or “torque” of golfclubs can select “best” golf clubs that provide “flex” and/or “torque”to their individual preferences.

[0066] It is to be noted that shafts with different diameters willprovide different properties. Materials of shafts will greatly affectproperties as well. Other physical properties of shafts would alsoaffect properties of golf clubs. Sizes and/or weights of club heads alsoaffect properties of golf clubs.

[0067] While the invention has been described using various embodiments,alterations or modifications to the embodiments may be made within thescope of the invention as defined in the “claims”, which are allintended to be within the scope of the present invention.

What is claimed is:
 1. A golf club shaft made from a shaft rod havingthereon at least one marking which comprises cutting information to beutilized in a shaft cutting operation so as to provide said golf clubshaft with a desired performance property.
 2. A golf club shaftaccording to claim 1, wherein said marking is provided in a length whichfacilitates utilization thereof after said shaft has been incorporatedinto a golf club.
 3. A golf club shaft according to claim 1, whereinsaid marking comprises scale.
 4. A golf club shaft according to claim 3,wherein said scale is calibrated at intervals between 1 mm and 13 mm. 5.A golf club shaft according to claim 3, wherein said scale is calibratedat 5 mm intervals.
 6. A golf club shaft according to claim 3, whereinsaid scale is calibrated at 10 mm intervals.
 7. A golf club shaftaccording to claim 3, wherein said scale is calibrated at ½ inchintervals.
 8. A golf club shaft according to claim 3, wherein said scaleis calibrated at ¼ inch intervals.
 9. A golf club shaft according toclaim 3, wherein said scale includes length indicating numerals.
 10. Agolf club shaft according to claim 1, wherein said marking is providedon said shaft to be out of sight of a player who is addressing a ballusing a golf club incorporating said shaft.
 11. A golf club shaftaccording to claim 1, wherein said marking is provided on said shaft rodat a tip end portion thereof.
 12. A golf club shaft according to claim1, wherein said marking is provided on said shaft rod at a butt endportion thereof.
 13. A golf club shaft according to claim 1, whereinsaid golf club shaft has been cut according to cutting informationprovided in a table of properties in relation to the length of a golfclub shaft made from a shaft rod on which said cutting information isprepared.
 14. A method for cutting a shaft rod to provide a golf clubshaft, comprising the step of cutting said shaft rod according to amarking comprising cutting information which is provided on said shaftrod.
 15. A method for cutting a shaft rod to provide a golf clubaccording to claim 14, said cutting information comprising scale whichis calibrated at 10 mm intervals.
 16. A method for cutting a shaft rodto provide a golf club according to claim 14, said cutting informationcomprising scale calibrated at 5 mm intervals.
 17. A method for cuttinga shaft rod to provide a golf club according to claim 14, said cuttinginformation comprising scale calibrated at ½ inch intervals.
 18. Amethod for cutting a shaft rod to provide a golf club according to claim14, said cutting information comprising scale calibrated at ¼ inchintervals.
 19. A method for cutting a shaft rod to provide a golf clubaccording to claim 14, wherein cutting by said method is performedaccording to cutting information provided in a table of properties inrelation to the length of a golf club shaft made from a shaft rod onwhich said cutting information is prepared.